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* [binutils-gdb] GDB: Fix the mess with value byte/bit range types
@ 2023-02-10 23:50 Maciej W. Rozycki
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From: Maciej W. Rozycki @ 2023-02-10 23:50 UTC (permalink / raw)
To: gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4f82620cc9fd1ef630b6b732a9d939d4e529a07f
commit 4f82620cc9fd1ef630b6b732a9d939d4e529a07f
Author: Maciej W. Rozycki <macro@embecosm.com>
Date: Fri Feb 10 23:49:19 2023 +0000
GDB: Fix the mess with value byte/bit range types
Consistently use the LONGEST and ULONGEST types for value byte/bit
offsets and lengths respectively, avoiding silent truncation for ranges
exceeding the 32-bit span, which may cause incorrect matching. Also
report a conversion overflow on byte ranges that cannot be expressed in
terms of bits with these data types, e.g.:
(gdb) print one_hundred[1LL << 58]
Integer overflow in data location calculation
(gdb) print one_hundred[(-1LL << 58) - 1]
Integer overflow in data location calculation
(gdb)
Previously such accesses would be let through with unpredictable results
produced.
Diff:
---
gdb/value.c | 43 ++++++++++++++++++++++++++-----------------
gdb/value.h | 8 ++++----
2 files changed, 30 insertions(+), 21 deletions(-)
diff --git a/gdb/value.c b/gdb/value.c
index 09e10b9a8b1..57625b005ac 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -74,7 +74,7 @@ struct range
LONGEST offset;
/* Length of the range. */
- LONGEST length;
+ ULONGEST length;
/* Returns true if THIS is strictly less than OTHER, useful for
searching. We keep ranges sorted by offset and coalesce
@@ -97,10 +97,10 @@ struct range
[offset2, offset2+len2) overlap. */
static int
-ranges_overlap (LONGEST offset1, LONGEST len1,
- LONGEST offset2, LONGEST len2)
+ranges_overlap (LONGEST offset1, ULONGEST len1,
+ LONGEST offset2, ULONGEST len2)
{
- ULONGEST h, l;
+ LONGEST h, l;
l = std::max (offset1, offset2);
h = std::min (offset1 + len1, offset2 + len2);
@@ -112,7 +112,7 @@ ranges_overlap (LONGEST offset1, LONGEST len1,
static int
ranges_contain (const std::vector<range> &ranges, LONGEST offset,
- LONGEST length)
+ ULONGEST length)
{
range what;
@@ -380,7 +380,8 @@ get_value_arch (const struct value *value)
}
int
-value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
+value_bits_available (const struct value *value,
+ LONGEST offset, ULONGEST length)
{
gdb_assert (!value->lazy);
@@ -389,8 +390,16 @@ value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
int
value_bytes_available (const struct value *value,
- LONGEST offset, LONGEST length)
+ LONGEST offset, ULONGEST length)
{
+ ULONGEST sign = (1ULL << (sizeof (ULONGEST) * 8 - 1)) / TARGET_CHAR_BIT;
+ ULONGEST mask = (sign << 1) - 1;
+
+ if (offset != ((offset & mask) ^ sign) - sign
+ || length != ((length & mask) ^ sign) - sign
+ || (length > 0 && (~offset & (offset + length - 1) & sign) != 0))
+ error (_("Integer overflow in data location calculation"));
+
return value_bits_available (value,
offset * TARGET_CHAR_BIT,
length * TARGET_CHAR_BIT);
@@ -460,7 +469,7 @@ value_entirely_optimized_out (struct value *value)
static void
insert_into_bit_range_vector (std::vector<range> *vectorp,
- LONGEST offset, LONGEST length)
+ LONGEST offset, ULONGEST length)
{
range newr;
@@ -558,8 +567,8 @@ insert_into_bit_range_vector (std::vector<range> *vectorp,
if (ranges_overlap (bef.offset, bef.length, offset, length))
{
/* #1 */
- ULONGEST l = std::min (bef.offset, offset);
- ULONGEST h = std::max (bef.offset + bef.length, offset + length);
+ LONGEST l = std::min (bef.offset, offset);
+ LONGEST h = std::max (bef.offset + bef.length, offset + length);
bef.offset = l;
bef.length = h - l;
@@ -600,7 +609,7 @@ insert_into_bit_range_vector (std::vector<range> *vectorp,
struct range &r = *i;
if (r.offset <= t.offset + t.length)
{
- ULONGEST l, h;
+ LONGEST l, h;
l = std::min (t.offset, r.offset);
h = std::max (t.offset + t.length, r.offset + r.length);
@@ -626,14 +635,14 @@ insert_into_bit_range_vector (std::vector<range> *vectorp,
void
mark_value_bits_unavailable (struct value *value,
- LONGEST offset, LONGEST length)
+ LONGEST offset, ULONGEST length)
{
insert_into_bit_range_vector (&value->unavailable, offset, length);
}
void
mark_value_bytes_unavailable (struct value *value,
- LONGEST offset, LONGEST length)
+ LONGEST offset, ULONGEST length)
{
mark_value_bits_unavailable (value,
offset * TARGET_CHAR_BIT,
@@ -786,7 +795,7 @@ static int
find_first_range_overlap_and_match (struct ranges_and_idx *rp1,
struct ranges_and_idx *rp2,
LONGEST offset1, LONGEST offset2,
- LONGEST length, ULONGEST *l, ULONGEST *h)
+ ULONGEST length, ULONGEST *l, ULONGEST *h)
{
rp1->idx = find_first_range_overlap (rp1->ranges, rp1->idx,
offset1, length);
@@ -1306,14 +1315,14 @@ value_contents_all (struct value *value)
static void
ranges_copy_adjusted (std::vector<range> *dst_range, int dst_bit_offset,
const std::vector<range> &src_range, int src_bit_offset,
- int bit_length)
+ unsigned int bit_length)
{
for (const range &r : src_range)
{
- ULONGEST h, l;
+ LONGEST h, l;
l = std::max (r.offset, (LONGEST) src_bit_offset);
- h = std::min (r.offset + r.length,
+ h = std::min ((LONGEST) (r.offset + r.length),
(LONGEST) src_bit_offset + bit_length);
if (l < h)
diff --git a/gdb/value.h b/gdb/value.h
index f022510ded1..80f92597d07 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -505,7 +505,7 @@ extern int value_bits_synthetic_pointer (const struct value *value,
byte is unavailable. */
extern int value_bytes_available (const struct value *value,
- LONGEST offset, LONGEST length);
+ LONGEST offset, ULONGEST length);
/* Given a value, determine whether the contents bits starting at
OFFSET and extending for LENGTH bits are available. This returns
@@ -513,7 +513,7 @@ extern int value_bytes_available (const struct value *value,
bit is unavailable. */
extern int value_bits_available (const struct value *value,
- LONGEST offset, LONGEST length);
+ LONGEST offset, ULONGEST length);
/* Like value_bytes_available, but return false if any byte in the
whole object is unavailable. */
@@ -527,13 +527,13 @@ extern int value_entirely_unavailable (struct value *value);
LENGTH bytes as unavailable. */
extern void mark_value_bytes_unavailable (struct value *value,
- LONGEST offset, LONGEST length);
+ LONGEST offset, ULONGEST length);
/* Mark VALUE's content bits starting at OFFSET and extending for
LENGTH bits as unavailable. */
extern void mark_value_bits_unavailable (struct value *value,
- LONGEST offset, LONGEST length);
+ LONGEST offset, ULONGEST length);
/* Compare LENGTH bytes of VAL1's contents starting at OFFSET1 with
LENGTH bytes of VAL2's contents starting at OFFSET2.
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